Evolution Flashcards
1
Q
- earliest ancestor of the horse, about 60 mya (Eocene)
- about 2 feet in height, the size of a cat or a dog
- arched back and snout-like noses
A
Eohippus
2
Q
- about 40 mya, Oligocene
- about 24 inches at the shoulder
- back less arched, face, snout and neck somewhat
longer - six grinding cheek teeth with single premolar in front
for grinding down tough vegetation
A
Mesohippus
3
Q
- effective grazer and runner
- middle of Miocene epoch about 30 mya
- wider molar for crunching hard grasses
- hindlegs relatively short
- 3 toes on each foot, side toes almost useless but center
was long and strong and ended in a curved hoof which
bore all of the animal’s weight
A
Merychippus
4
Q
- during the Pliocene (Ice Age) period, 10 mya
- grew bigger that their ancestors and looked like the
modern horse - teeth strongly curved but became better fitted for
eating grass - side toes became short bones along the leg leaving the
middle toe with its hoof to support the animal - skull had a deep facial fossa
- long and slim limbs reveal quick-footed animal
A
Pliohippus
